PB2303: THROMBOCYTOPENIA IN COVID-19 PATIENTS ON ECMO SUPPORT
Authors: C. Jones, K. Chen, V. Narendran
Journal: HemaSphere (2022)

Background: Thrombocytopenia is a common complication of COVID-19 (coronavirus disease 2019). The possible mechanisms include decreased platelet production, increased platelet destruction, and consumption. According to studies, thrombocytopenia indicates a poor prognosis and increased mortality in COVID-19 patients. Meanwhile, thrombocytopenia is often complicated in ECMO (extracorporeal membrane oxygenation) due to shearing force in the circuit and heparin-induced thrombocytopenia (HIT). COVID-19 patients who are managed on ECMO are at high risk of developing thrombocytopenia and life-threatening bleeding. Aims: Venous thromboembolism prevention is critical in managing COVID-19 patients. The balance between bleeding secondary to thrombocytopenia and thromboembolic prophylaxis is challenging. ECMO support also increases the risk of thrombocytopenia. Our retrospective observation study reports the incidences of thrombocytopenia and major bleeding events in twenty-three COVID-19 patients who were managed with ECMO. Methods: We retrospectively reviewed the data of twenty-three patients who were diagnosed with COVID-19 and managed on ECMO. Thrombocytopenia is defined by platelet level lower than 150,000/uL. Incidences of thrombocytopenia and related complications were recorded and analyzed. Results: Twenty-three adult patients who were diagnosed with COVID-19 received ECMO support. The mean age of patients was 45-year-old and mean body mass index (BMI) was 31.29. Seventeen patients were males, and eleven patients had at least one of the following pre-ECMO comorbidity: ten (43.5%) patients had hypertension, eleven (47.8%) patients had type 2 diabetes and four (17.3%) patients had hyperlipidemia. None of the patients were active smokers or had chronic lung disease when admitted. Anticoagulation was initiated on the day of admission. Twenty-one (91.3%) patients developed thrombocytopenia and HIT was excluded. Eighteen (78.3%) patients had hemorrhage requiring transfusion, with the gastrointestinal tract being the most common site. Other bleeding sites included brain, chest, tracheostomy area and cannulation site. Thromboembolic prophylaxis was held for active bleeding or platelet count threshold of < 30,000/uL. The overall mortality rate was 70.0%. Image:Summary/Conclusion: Based on our data, the incidence of thrombocytopenia was 91.3% in ECMO-managed COVID-19 patients; 78.3% patients developed hemorrhage requiring transfusion. Given the high risk of thromboembolic events in COVID-19 patients, anticoagulation is recommended to all hospitalized COVID-19 patients unless there is active bleeding, previous bleeding history within three days or platelet count is lower than 30,000 cells/uL. However, anticoagulation further increases the risk of bleeding in the setting of thrombocytopenia, which may lead to sudden deterioration and death. Further investigation into the mechanisms, implications, and management of thrombocytopenia will lead to significantly improved outcomes and prognosis for COVID-19 patients who are managed on ECMO.